Jennifer Valentine GALLEGO BASIC ELEMENTARY SCHOOL, TUCSON, AZ
3rd Grade Math : Unit #6 - Time : Lesson #4

Lucky Luggage Tags: An International Challenge

Objective: SWBAT review telling time to the hour and rounding time to the nearest hour and will use this skill to calculate the end time of a trip starting in NYC and ending in another country.
Standards: 3.MD.A.1 MP1 MP2 MP4 MP5 MP7
Subject(s): Math
60 minutes
1 Opener - 10 minutes

It is helpful to have a globe handy to open this lesson.  

I show students Tucson and remind them of the time it takes to fly from Tucson to Boston, or Tucson to San Diego.  Then I show them Boston to London and guide them into making the connection that while the flight is very different in some ways (across the Atlantic, to another country) it is approximately the same distance.  This prevents them from jumping from a 5 hour cross country flight to saying it would take 5 days to fly to Spain.  

I run my fingers up and down the longitude lines and remind them, as I'm turning the globe to the east, that the time zone difference between Tucson/ the U.S. increases the further eastward we travel around the globe. I also give them examples of layovers, which provides additional context to real world travel.   

There are layers of real-world complexity in this problem and students are working not just with specific mathematical skills but also the very important mathematical practice 1: of make sense of problems and persevering in solving them.  They need to work to understand the components of the question before they will begin to work at solving it!  

2 Guided Practice - 36 minutes

This additional practice with calculating elapsed time to the closest hour further strengthens students ability to travel over the "12 mark".  This is where most difficulty arises when calculating elapsed time.  Additionally, we are further practicing the basic facts used in adding up to 12.  An additional layer of complexity in these problems arises from the need to change the start time to the time zone of the end time of the flight, prior to calculating the elapsed time. I explicitly state that we have to be using the same system, in this case time zones, before we can make a comparison.  Again, here students have to first make sense of the problem (MP1) before they reason very abstractly and quantitatively. (MP2)

I monitor the students closely throughout the Lucky Luggage Tags - International Guided Practice and ask extension (What if there was a 3 1/2 hour layover in Paris?) and scaffolding (Restate the first step.  Yes, we need to convert the start time to the time zone of the end time.) questions in order to differentiate within the context of a whole group lesson.  They need consistent support in looking for and making use of the provided structure (MP7) in this problem: change to the end time zone, round to the closest hour, calculate.  There is rarely one right system to use in mathematics, but it is important to have a system!

This is a tricky concept, so we spend today working through it together and then in tomorrow's lesson, when I ask them to continue with this but work with elapsed time to the closest five minutes, they have had adequate support.   This lesson is a great way to build upon their ability to model with mathematics (MP4) and use appropriate tools strategically (MP5).

Note: If you want to look up other cities in addition to those used in this lesson, the Time and Date World Clock is a helpful site.

3 Independent Practice - 14 minutes

I give students Lucky Luggage Tags International Exit Ticket to work through on their own.  It is more important that they do quality work than that they complete a large quantity of problems.  Giving them this one page allows me to easily monitor them and take anecdotal notes about who might need enrichment and who needs extra assistance.

Exit Ticket
Adjustments to Practice

This is a lesson with many layers and it's essential that as soon as possible after lessons such as this I sit down and write a few notes to myself about what worked, what didn't, and what I'd like to change in how I present it.  Then I go over the exit tickets and take notes on student strengths and misconceptions and put them into groups for the next lesson.  I may not actually physically separate them out, but instead sometimes keep the list on my clipboard so I know who I'm enriching and who needs extra support.  

When I talk about changes, it is frequently something very subtle about how I worded a question.  It is helpful that when my students don't understand something, they persist in explaining to me what they are thinking.  This allows me to fine tune what I'm doing.  Every class is different and even if I have taught a lesson several times, it always changes. I have changed and learned more, and the students before me change as well, all with different needs.